1. Field of the Invention
The present invention generally relates to a semiconductor device and a method of manufacturing thereof, and particularly relates to a semiconductor device having a plurality of semiconductor chips provided in a stacked structure and a method of manufacturing thereof.
Recently, in the field of semiconductor devices, there is an increasing need for a high density mounting method for providing smaller, thinner, and lighter structures. In order to satisfy the above need, semiconductor devices of a Multi Chip Module (MCM) structure have become of great interest.
The mounting level of the MCM is substantially the same as that of a Chip Size Package (CSP). Also, with the MCM, a plurality of semiconductor chips is mounted on a multilayer printed circuit board by wire bonding or flip-chip bonding.
2. Description of the Related Art
It is known to provide a plurality of semiconductor chips on a multilayer printed circuit board by wire bonding or flip-chip bonding. Such a structure has a drawback in that the area of the multilayer printed circuit board cannot be reduced, since the semiconductor chips are provided on the multilayer printed circuit board in a two-dimensional manner.
Also, it is known to provide a plurality of semiconductor chips on both sides of a multilayer printed circuit board. Such a structure has a drawback in that a sealing resin must be provided on both sides of the multilayer printed circuit board.
Further, it is known to provide a plurality of semiconductor chips on a single layer printed circuit board in such a manner that the semiconductor chips are stacked directly on each other. Such a structure has a drawback that the semiconductor chips will interfere with each other. Also, inexpensive general-purpose semiconductor chips cannot be used in such a semiconductor devices, since their predetermined pin layout may cause an interference between the wires.
Accordingly, it is a general object of the present invention to provide a semiconductor device that can solve the above problems.
It is another and more specific object of the present invention to provide a semiconductor device having a reduced size, an improved mounting reliability and the ability to use general-purpose semiconductor chips.
In order to achieve the above objects according to the present invention, the semiconductor device includes:
a first semiconductor chip;
a second semiconductor chip;
a multilayer printed circuit board having a first surface whereon the first semiconductor chip is mounted and a second surface whereon external connection terminals are provided;
an interposer; and
a sealing resin for sealing the first and second semiconductor chips,
wherein the interposer holds the second semiconductor chip above the first semiconductor chip such that there is a separation between the first semiconductor chip and the second semiconductor chip while electrically connecting the second semiconductor chip and the multilayer printed circuit board, and
the sealing resin is formed so as to fill the separation between the first semiconductor chip and the second semiconductor chip.
With the semiconductor device described above, the size of the semiconductor device can be reduced since the second semiconductor chip is held above the first semiconductor chip such that there is a separation between the first semiconductor chip and the second semiconductor chip. Also, since there is no need to provide wirings on the interposer at a position peripheral to the multilayer printed circuit board, general-purpose semiconductor chips can be used. Therefore, the cost of the semiconductor device can be reduced. Further, in the sealing resin, the first semiconductor chip and the second semiconductor chip are held with a separation between each other. Therefore, the semiconductor chips will not interfere with each other, and there liability of the semiconductor device can be improved.
It is still another object of the present invention to provide a method of manufacturing the above-described semiconductor device.
In order to achieve the above objects according to the present invention, a method of manufacturing a semiconductor device includes comprising the steps of:
a) mounting a first semiconductor chip on an upper surface of a multilayer printed circuit board and electrically connecting the first semiconductor to the multilayer printed circuit board;
b) mounting a second semiconductor chip on a stage of a lead frame and electrically connecting the second semiconductor chip and lead parts of the lead frame by means of first electrical connection parts;
c) holding the lead frame on the multilayer printed circuit board by a holding means such that there is a separation between the second semiconductor chip and the first semiconductor chip;
d) connecting the lead parts and the multilayer printed circuit board by means of second electrical connection parts;
e) forming a sealing resin such that the first semiconductor chip and the second semiconductor chip are sealed and the separation between the second semiconductor chip and the first semiconductor chip is filled with the sealing resin; and
f) forming external connection terminals on a lower surface of the multilayer printed circuit board.
With the method described above, the connection step and the resin sealing step can be implemented with the second semiconductor chip being held above the first semiconductor chip with a separation between each other. Therefore, the connection step and the resin sealing step can be implemented quite easily.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.